Geologic map of the Battle Ground 7.5-minute quadrangle, Clarke County, Washington

Soil and vegetation hide many geologic features in the area, and suburban development hinders access behind the many roads. For the present study, observations from 21 days of field mapping were compared against logs, summaries, and interpretations of field-located water wells (Mundorff, 1964; Swanson and others, 1993) and supplemented by interpreting drillers logs of about 1,000 approximately located water wells. The resulting geologic-map interpretation relies on key outcrops, on geomorphic position of units, and on the well logs to indicate the projected surface positions of poorly exposed units. Several dozen well logs supplemented the field observations used to draw (vertically exaggerated) cross section A-A', for example.

This digital map publication, generated from new mapping by the author, shows the general distribution of bedrock and surficial deposits in the Battle Ground 7.5' quadrangle. Together with the accompanying geologic description pamphlet, it presents current knowledge of the geologic structure and stratigraphy of the area covered. The database identifies map units that are classified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source map limits the spatial resolution (scale) of the database to 1:24,000 or smaller. The content and character of the digital publication, as well as methods of obtaining the digital files, are described below.
The databases in this report were compiled in ARC/INFO, a commercial Geographic Information System by Environmental Systems Research Institute (ESRI) in Redlands, California, with version 3.0 of the menu interface ALACARTE (Fitzgibbon and Wentworth, 1991; Fitzgibbon, 1991; Wentworth and Fitzgibbon, 1991). The files are in either GRID (ARC/INFO raster data) format or COVERAGE (ARC/INFO vector data) format. Coverages are stored in uncompressed ARC export format (ARC/INFO version 8.1.2 for Unix). ARC/INFO export files (files with the .e00 extension) can be converted into ARC/INFO coverages in ARC/INFO (see below) and can be read by some other Geographic Information Systems, such as MapInfo, via ArcLink and ESRI's ArcView (version 1.0 for Windows 3.1 to 3.11 is available for free from ESRI's web site: http://www.esri.com). The digital compilation was done in version 8.1.2 of ARC/INFO for Unix.
Several different coverages were generated during the construction of the Battle Ground quadrangle geologic map. The topographic base map remains as an image and then is converted to a grid, and is merged at the last step with the colored geology polygrids. The image was merged with the geology grid to give an apparent transparent color image of both combined. The raster geology grids were converted to vector coverages with ARC/INFO's gridline routine. Alacarte and some custom menus and AMLs (ARC Macro Language) were used to project, transform, edit, tag, and build lines, polygons, and points in the map. A digital layout or map collar was made with Adobe Illustrator. The plot AMLs run in ARC/INFO and call the coverages, grids, and Adobe Illustrator EPS files to make uncompressed PostScript files.